fix(reranker): support omitting top_n (#7199)

* fix(reranker): support omitting top_n

Signed-off-by: Mikhail Khludnev <mkhl@apache.org>

* fix(reranker): support omitting top_n

Signed-off-by: Mikhail Khludnev <mkhl@apache.org>

* pass 0 explicitly 

Signed-off-by: Mikhail Khludnev <mkhludnev@users.noreply.github.com>

---------

Signed-off-by: Mikhail Khludnev <mkhl@apache.org>
Signed-off-by: Mikhail Khludnev <mkhludnev@users.noreply.github.com>

Author: mkhludnev

backend/python/rerankers/backend.py

@@ -75,12 +75,13 @@ def Rerank(self, request, context):
             documents.append(doc)
         ranked_results=self.model.rank(query=request.query, docs=documents, doc_ids=list(range(len(request.documents))))
         # Prepare results to return
+        cropped_results = ranked_results.top_k(request.top_n) if request.top_n > 0 else ranked_results
         results = [
             backend_pb2.DocumentResult(
                 index=res.doc_id,
                 text=res.text,
                 relevance_score=res.score
-            ) for res in ranked_results.top_k(request.top_n)
+            ) for res in (cropped_results)
         ]
 
         # Calculate the usage and total tokens

backend/python/rerankers/test.py

@@ -76,7 +76,35 @@ def test_rerank(self):
                 )
                 response = stub.LoadModel(backend_pb2.ModelOptions(Model="cross-encoder"))
                 self.assertTrue(response.success)
-               
+
+                rerank_response = stub.Rerank(request)
+                print(rerank_response.results[0])
+                self.assertIsNotNone(rerank_response.results)
+                self.assertEqual(len(rerank_response.results), 2)
+                self.assertEqual(rerank_response.results[0].text, "I really like you")
+                self.assertEqual(rerank_response.results[1].text, "I hate you")
+        except Exception as err:
+            print(err)
+            self.fail("Reranker service failed")
+        finally:
+            self.tearDown()
+
+    def test_rerank_omit_top_n(self):
+        """
+        This method tests if the embeddings are generated successfully even top_n is omitted
+        """
+        try:
+            self.setUp()
+            with grpc.insecure_channel("localhost:50051") as channel:
+                stub = backend_pb2_grpc.BackendStub(channel)
+                request = backend_pb2.RerankRequest(
+                    query="I love you",
+                    documents=["I hate you", "I really like you"],
+                    top_n=0 # 
+                )
+                response = stub.LoadModel(backend_pb2.ModelOptions(Model="cross-encoder"))
+                self.assertTrue(response.success)
+
                 rerank_response = stub.Rerank(request)
                 print(rerank_response.results[0])
                 self.assertIsNotNone(rerank_response.results)
@@ -91,7 +119,7 @@ def test_rerank(self):
 
     def test_rerank_crop(self):
         """
-        This method tests if the embeddings are generated successfully
+        This method tests top_n cropping
         """
         try:
             self.setUp()
@@ -104,7 +132,7 @@ def test_rerank_crop(self):
                 )
                 response = stub.LoadModel(backend_pb2.ModelOptions(Model="cross-encoder"))
                 self.assertTrue(response.success)
-               
+
                 rerank_response = stub.Rerank(request)
                 print(rerank_response.results[0])
                 self.assertIsNotNone(rerank_response.results)
@@ -115,4 +143,4 @@ def test_rerank_crop(self):
             print(err)
             self.fail("Reranker service failed")
         finally:
-            self.tearDown()
+            self.tearDown()